Hydroconversion Multi-Metallic Catalyst and Method for Making Thereof

ABSTRACT

A catalyst precursor for preparing a bulk multi-metallic catalyst upon sulfidation is provided. The precursor has an essentially monomodal pore volume distribution with at least 90% of the pores being macropores, and a total pore volume of at least 0.08 g/cc. The bulk multi-metallic prepared from the precursor is particularly suitable for hydrotreating heavy oil feeds having a boiling point in the range of 343° C. (650° F.)—to 454° C. (850° F.), an average molecular weight Mn ranging from 300 to 400, and an average molecular diameter ranging from 0.9 nm to 1.7 nm.

CROSS-REFERENCE TO RELATED APPLICATIONS

NONE.

TECHNICAL FIELD

The invention relates generally to a hydroprocessing catalyst precursor,processes for preparing the catalyst precursor, multi-metallic catalystsprepared using the catalyst precursor, and hydroconversion processesemploying the multi-metallic catalysts.

BACKGROUND

The petroleum industry is increasingly turning to heavy crudes, resids,coals and tar sands, i.e., lower grade hydrocarbon (“heavy oil”), assources for feedstocks. The upgrading or refining of these feedstocks isaccomplished by treating the feedstocks with hydrogen in the presence ofcatalysts to effect conversion of at least a portion of the feeds tolower molecular weight hydrocarbons, or to effect the removal ofunwanted components, or compounds, or their conversion to innocuous orless undesirable compounds.

In the hydroconversion process, it is desirable to employ catalysthaving sufficient open volume (porosity) for low mass transferresistance and facilitate efficient through flow of reactors, while atthe same the specific area of each catalyst body should be as large aspossible to increase exposure of the reactants to the catalyst material.However, a catalyst that is highly porous does not necessarily mean thatthe catalyst has a lot of surface area. The catalyst may be too porous,having very little in terms of surface area and correspondingly, lowcatalytic activity in terms of reactive sites.

There is a need for a bulk/unsupported catalyst for use in thehydroconversion of lower grade hydrocarbon with improved performance,i.e., providing high yield conversions with optimum porosity and surfacearea. There is also a need for a bulk multi-metallic catalyst havingsufficient pore volume/size for hydrotreating heavy oil feeds.

SUMMARY OF THE INVENTION

In one aspect, a process for hydrotreating a hydrocarbon feed underhydroprocessing conditions is provided. The process comprises contactingthe hydrocarbon feed with a bulk multi-metallic catalyst prepared bysulfiding a catalyst precursor comprising at least a Group VIB metalcompound; at least a promoter metal compound selected from Group VIII,Group IIB, Group IIA, Group IVA and combinations thereof, optionally atleast a ligating agent; optionally at least a diluent; the catalystprecursor after being shaped, having an essentially monomodal pore sizedistribution with at least 95% of the pores being macropores and a totalpore volume of at least 0.08 g/cc.

In one aspect, a catalyst precursor, upon sulfidation, forms abulk-multimetallic catalyst for hydrotreating a hydrocarbon feed underhydroprocessing conditions is provided. The catalyst precursor comprisesat least a Group VIB metal compound; at least a promoter metal compoundselected from Group VIII, Group IIB, Group IIA, Group IVA andcombinations thereof, optionally at least a ligating agent; optionallyat least a diluent. The catalyst precursor after being shaped, has anessentially monomodal pore size distribution with at least 95% of thepores being macropores and a total pore volume of at least 0.08 g/cc.

In yet another aspect, a process to prepare a bulk multi-metalliccatalyst for hydrotreating a hydrocarbon feed is provided. The processcomprising: providing at least a Group VIII metal precursor M^(VIB) andat least promoter metal precursor M^(P), the promoter metal precursorM^(P) is selected from the group of Group VIII, Group IIB, Group IIA,Group IVA and c^(ombi)nations thereof, has an oxidation stat^(e) ofeither +2 or +4; combining the at least a Group VIII and the atleas^(t a) promoter metal precursor to form a cata yst precursorprecipitate in a l^(i)quid solution; separating the catalyst precursorprecipitate from the liquid so^(luti)on forming a filter cake; dryingthe ^(c)atalyst precursor filter cake by a non-agglomerative dryingmethod, obtaining catalyst precursor particles; adding to the catalystprecursor particles at least one of shaping aid agent, a pore formingagent, a peptizing agent, a diluent, and combinations thereof, forming abatch mixture; shaping the batch mixture forming a shaped catalystprecursor; sulfiding the shaped catalyst precursor forming the bulkmulti-metallic catalyst.

In yet another aspect, a process to prepare a multi-metallic catalystcomposition for hydrotreating a hydrocarbon feed is provided. Theprocess comprising: providing at least a Group VIII metal precursorM^(VIB) and at least promoter metal precursor M^(P), the promoter metalprecursor M^(P) is selected from the group of Group VIII, Group IIB,Group IIA, Group IVA and combinations thereof, has an oxidation state ofeither +2 or +4; combining the at least a Group VIII and the at least apromoter metal precursor to form a catalyst precursor precipitate in aliquid solution; separating the catalyst precursor precipitate from theliquid solution forming a filter cake; treating the filter cake with atleast a ligating agent forming a chelated catalyst precursor; drying andshaping the chelated catalyst precursor, forming a shaped catalystprecursor; and sulfiding the shaped catalyst precursor forming the bulkmulti-metallic catalyst.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is block diagram showing an embodiment of a process for making amulti-metallic catalyst incorporating rework materials.

DETAILED DESCRIPTION

The following terms will be used throughout the specification and willhave the following meanings unless otherwise indicated.

SCF/BBL (or scf/bbl, or scfb or SCFB) refers to a unit of standard cubicfoot of gas (N₂, H₂, etc.) per barrel of hydrocarbon feed.

LHSV means liquid hourly space velocity.

The Periodic Table referred to herein is the Table approved by IUPAC andthe U.S. National Bureau of Standards, an example is the Periodic Tableof the Elements by Los Alamos National Laboratory's Chemistry Divisionof October 2001.

As used here, the term “bulk catalyst” may be used interchangeably with“unsupported catalyst,” meaning that the catalyst composition is NOT ofthe conventional catalyst form which has a preformed, shaped catalystsupport which is then loaded with metals via impregnation or depositioncatalyst. In one embodiment, the bulk catalyst is formed throughprecipitation. In another embodiment, the bulk catalyst has a binderincorporated into the catalyst composition. In yet another embodiment,the bulk catalyst is formed from metal compounds and without any binder.

As used herein, the phrases “one or more of” or “at least one of” whenused to preface several elements or classes of elements such as X, Y andZ or X₁-X_(n), Y₁-Y_(n) and Z₁-Z_(n), is intended to refer to a singleelement selected from X or Y or Z, a combination of elements selectedfrom the same common class (such as X₁ and X₂), as well as a combinationof elements selected from different classes (such as X₁, Y₂ and Zn).

As used herein, “hydroconversion” or “hydroprocessing” is meant anyprocess that is carried out in the presence of hydrogen, including, butnot limited to, methanation, water gas shift reactions, hydrogenation,hydrotreating, hydrodesulphurization, hydrodenitrogenation,hydrodemetallation, hydrodearomatization, hydroisomerization,hydrodewaxing and hydrocracking including selective hydrocracking.Depending on the type of hydroprocessing and the reaction conditions,the products of hydroprocessing can show improved viscosities, viscosityindices, saturates content, low temperature properties, volatilities anddepolarization, etc.

As used herein, 700° F.+ conversion rate refers to the conversion of afeedstock having a boiling point of greater than 700° F.+ to less than700° F. (371.0° C.) boiling point materials in a hydroconversionprocess, computed as (100%*(wt. % boiling above 700° F. materials infeed−wt. % boiling above 700° F. materials in products)/wt. % boilingabove 700° F. materials in feed)).

As used herein, “LD50” is the amount of a material, given all at once,causes the death of 50% (one half) of a group of test animals. LD-50measures the short-term poisoning potential (acute toxicity) of amaterial with the testing being done with smaller animals such as ratsand mice (in mg/Kg).

As used herein, “shaped catalyst precursor” means catalyst precursorformed (or shaped) by spray drying, pelleting, pilling, granulating,beading, tablet pressing, bricketting, using compression method viaextrusion or other means known in the art or by the agglomeration of wetmixtures. The shaped catalyst precursor can be in any form or shape,including but not limited to pellets, cylinders, straight or rifled(twisted) trilobes, multiholed cylinders, tablets, rings, cubes,honeycombs, stars, tri-lobes, quadra-lobes, pills, granules, etc.

As used herein, pores are classified according to size into threecategories; micropores (dimension smaller than 3.5 nm), mesopores(dimension ranging from 3.5-500 nm) and macropores (dimension largerthan 500 nm).

Pore porosity and pore size distribution in one embodiment are measuredusing mercury intrusion porosimetry, designed as ASTM standard method D4284. In another embodiment, pore porosity and size distribution aremeasured via the nitrogen adsorption method. Unless indicated otherwise,pore porosity is measured via the mercury intrusion method.

Catalyst Product: The hydroconversion bulk catalyst having low volumeshrinkage herein is formed from a catalyst precursor. The precursor isconverted into a catalyst (becoming catalytically active) uponsulfidation, e.g., for subsequent use in hydrodesulfurization (HDS),hydrodearomatization (HDA), and hydrodenitrification (HDN) processes.The starting material, i.e., catalyst precursor, can be a hydroxide oroxide material, prepared from at least a Promoter metal and a Group VIBmetal precursors. The metal precursors can be in either elemental orcompound form.

In one embodiment, the catalyst is prepared from a catalyst precursor inthe form of a bulk multi-metallic oxide comprising of at least one GroupVIII non-noble material and at least two Group VIB metals. In oneembodiment, the ratio of Group VIB metal to Group VIII non-noble metalranges from about 10:1 to about 1:10. In another embodiment, the oxidecatalyst precursor is of the general formula:(X)_(b)(MO)_(c)(W)_(d)O_(z); wherein X is Ni or Co, the molar ratio ofb:(c+d) is 0.5/1 to 3/1, the molar ratio of c:d is >0.01/1, and z=[2b+6(c+d)]/2. In yet another embodiment, the oxide catalyst precursorfurther comprises one or more ligating agents L. The term “ligand” maybe used interchangeably with “ligating agent,” “chelating agent” or“complexing agent” (or chelator, or chelant), referring to an additivethat combines with metal ions, e.g., Group VIB and/or Promoter metals,forming a larger complex, e.g., a catalyst precursor.

In another embodiment, the catalyst is prepared from a catalystprecursor in the form of a hydroxide comprising of at least one GroupVIII non-noble material and at least two Group VIB metals. In oneembodiment, the hydroxide compound is of the general formulaA_(v)[(M^(P))OH)_(x)(L)^(n) _(y)]_(z) (M^(VIB)O₄), wherein A is one ormore monovalent cationic species, M refers to at least a metal in theirelemental or compound form, and L refers to one or more ligating agents.

In yet another embodiment, the catalyst is prepared from a catalystprecursor with the inclusion of at least a diluent, the precursor is ofthe formula A_(r)[(M^(IIA))_(s)(M^(VIII))_(t)(Al)_(u)(OH)_(v)(L)_(w)]_(x)(Si_((1-y))Al_(y)O₂)_(z) (M^(VIB)O₄), wherein A is one or moremonovalent cationic species, M^(IIA) is one or more group IIA metals,M^(VIII) is one or more Group VIII metals, Al is aluminum, L is one ormore ligating agents, (Si_((1-y))Al_(y)O₂) is a silica-alumina moiety,M^(VIB) is one or more Group VIB metals with the atomic ratio ofM^(VII):M^(VIB) between 100:1 and 1:100.

In one embodiment, A is at least one of an alkali metal cation, anammonium, an organic ammonium and a phosphonium cation. In oneembodiment, A is selected from monovalent cations such as NH4+, otherquaternary ammonium ions, organic phosphonium cations, alkali metalcations, and combinations thereof.

In one embodiment, L is one or more ligating agents. In anotherembodiment, L is charge neutral or has a negative charge n<=0. Inanother embodiment, L is a non-toxic organic oxygen containing ligatingagent with an LD50 rate (as single oral dose to rats) of greater than500 mg/Kg. The term “charge-neutral” refers to the fact that thecatalyst precursor carries no net positive or negative charge. In oneembodiment, ligating agents include both polydentate as well asmonodentate, e.g., NH₃ as well as alkyl and aryl amines. Other examplesof ligating agents L include but are not limited to carboxylates,carboxylic acids, aldehydes, ketones, the enolate forms of aldehydes,the enolate forms of ketones, and hemiacetals, and combinations thereof.The term “carboxylate” refers to any compound containing a carboxylateor carboxylic acid group in the deprotonated or protonated state. Inanother embodiment, L is selected from the group of organic acidaddition salts such as formic acid, acetic acid, propionic acid, maleicacid, malic acid, cluconic acid, fumaric acid, succinic acid, tartaricacid, citric acid, oxalic acid, glyoxylic acid, aspartic acid, alkanesulfonic acids such as methane sulfonic acid and ethane sulfonic acid,aryl sulfonic acids such as benzene sulfonic acid and p-toluene sulfonicacid and arylcarboxylic acids; carboxylate containing compounds such asmaleate, formate, acetate, propionate, butyrate, pentanoate, hexanoate,dicarboxylate, and combinations thereof.

M^(P) is at least a promoter metal. In one embodiment, M^(P) has anoxidation state of either +2 or +4 depending on the Promoter metal(s)being employed. M^(P) is selected from Group VIII, Group IIB, Group IIA,Group IVA and combinations thereof. In one embodiment, M^(P) is at leasta Group VIII metal, M^(P) has an oxidation state P of +2. In anotherembodiment, M^(P) is selected from Group IIB, Group IVA and combinationsthereof. In one embodiment, the Promoter metal M^(P) is at least a GroupVIII metal, M^(P)having an oxidation state of +2 and the catalystprecursor is of the formula A_(v)[(M^(P)) (OH)_(x)(L)^(n) _(y)]_(z)(M^(VIB)O₄) to have (v−2+2z−x*z+n*y*z)=0. In one embodiment, thePromoter metal M^(P) is a mixture of two Group VIII metals such as Niand Co. In yet another embodiment, M^(P) is a combination of threemetals such as Ni, Co and Fe. In one embodiment where M^(P) is a mixtureof two group IIB metals such as Zn and Cd, the charge-neutral catalystprecursor is of the formulaA_(v)[(Zn_(a)Cd_(a)′)(OH)_(x)(L)_(n y)]_(z)(M^(VIB)O⁴).

In yet another embodiment, M^(P) is a combination of three metals suchas Zn, Cd and Hg, and the catalyst precursor is of the formulaA_(v)[(Zn_(a)Cd_(a)′Hg_(a)″)(OH)_(x)(L)_(n y)]_(z) (M^(VIB)O⁴).

In one embodiment, the Promoter metal M^(P) is selected from the groupof IIB and VIA metals such as zinc, cadmium, mercury, germanium, tin orlead, and combinations thereof, in their elemental, compound, or ionicform. In yet another embodiment, the Promoter metal M^(P) furthercomprises at least one of Ni, Co, Fe and combinations thereof, in theirelemental, compound, or ionic form. In another embodiment, the Promotermetal is a Group IIA metal compound, selected from the group ofmagnesium, calcium, strontium and barium compounds which are at leastpartly in the solid state, e.g., a water-insoluble compound such as acarbonate, hydroxide, fumarate, phosphate, phosphite, sulphide,molybdate, tungstate, oxide, or mixtures thereof.

In one embodiment, M^(VIB) is at least a Group VIB metal having anoxidation state of +6. In one embodiment, M^(P:MVIB) has an atomic ratiobetween 100:1 and 1:100. v−2+P*z−x*z+n*y*z=0; and 0≦y≦−P/n; 0≦x≦P;0≦v≦2; 0≦z. In one embodiment, M^(VIB) is molybdenum. In yet anotherembodiment, M^(VIB) is a mixture of at least two Group VIB metals, e.g.,molybdenum and tungsten.

Methods for Making Catalyst: The catalyst prepared herein has a lowvolume shrinkage in hydroprocessing operations, in combination with highmechanical strength and improved performance, i.e., providing high yieldconversions. The low shrinkage results from the controlled/optimizationof the thermal treatment of the catalyst precursor.

Reference will be made to FIG. 1, which is a block diagram schematicallyillustrating an embodiment of a general process for making amulti-metallic catalyst having an optimum pore volume and surface area.

Forming a Precipitate or Cogel: The first step 10 in the process is aprecipitation or cogellation step, which involves reacting in a mixtureof the metal precursors 11, e.g., Promoter metal component(s) and theGroup VIB metal component to obtain a precipitate or cogel. The term“cogel” refers to a co-precipitate (or precipitate) of at least twometal compounds. The metal precursors can be added to the reactionmixture as a solid, in solution, suspension, or a combination thereof.If soluble salts are added as such, they will dissolve in the reactionmixture and subsequently be precipitated or cogelled, or forming asuspension. The solution can be heated optionally under vacuum to effectprecipitation and evaporation of the liquid.

The precipitation (or cogelation) is carried out at a temperature and pHunder which the Promoter metal compound and the Group VIB metal compoundprecipitate or form a cogel. In one embodiment, the temperature at whichthe cogel is formed is between 25-350° C. In one embodiment, thecatalyst precursor is formed at a pressure between 0 to 3000 psig. In asecond embodiment, between 10 to 1000 psig. In a third embodiment,between 30 to 100 psig. The pH of the mixture can be changed to increaseor decrease the rate of precipitation or cogelation depending on thedesired characteristics of the product. In one embodiment, the mixtureis left at its natural pH during the reaction step(s). In anotherembodiment the pH is maintained in the range of 0-12. In anotherembodiment, the pH is maintained in the range of 7-10. Changing the pHcan be done by adding base or acid 12 to the reaction mixture, or addingcompounds, which decompose upon temperature increase into hydroxide ionsor H⁺ ions that respectively increase or decrease the pH. In anotherembodiment, adding compounds which participate in the hydrolysisreaction. Examples of compounds to be added for pH adjustment includebut are not limited to urea, nitrites, ammonium hydroxide, mineralacids, organic acids, mineral bases, and organic bases.

In one embodiment, at least a ligating agent L can be optionally addedprior to or after precipitation or cogelation of the promoter metalcompounds and/or Group VIB metal compounds, i.e., the ligating agent Lcan be added to the metal precursors as one of the reactors forming theprecipitate, or it can be added after the precipitate is formed. It isobserved that the incorporation of ligating agents in some embodimentssignificantly increase the porosity of the catalyst precursor. In oneembodiment, a chelated catalyst precursor shows a macropore volume of atleast 10% greater than an un-chelated catalyst precursor. In a secondembodiment, the macropore volume increase is at least 20%.

In one embodiment, instead of or in addition to the ligating agent L,diluent amounts from 5-95 wt. % of the total composition of the catalystprecursor can also be added to this step, depending on the envisagedcatalytic application. These materials can be applied before or afterthe precipitation or cogelation of the metal precursors. Examples ofdiluent materials include zinc oxide; zinc sulfide; niobia; tetraethylorthosilicate; silicic acid; titania; silicon components such as sodiumsilicate, potassium silicate, silica gels, silica sols, silica gels,hydronium- or ammonium-stabilized silica sols, and combinations thereof,aluminum components useful in the process of the present inventioninclude, but are not limited to, sodium aluminate, potassium aluminate,aluminum sulfate, aluminum nitrate, and combinations thereof, magnesiumcomponents such as magnesium aluminosilicate clay, magnesium metal,magnesium hydroxide, magnesium halides, magnesium sulfate, and magnesiumnitrate; zirconia; cationic clays or anionic clays such as saponite,bentonite, kaoline, sepiolite or hydrotalcite, or mixtures thereof. Inone embodiment, titania is used as a diluent in an amount of greaterthan 50 wt. %, on a final catalyst precursor basis (as an oxide orhydroxide).

Liquid Removal: In the next step 20, at least 50 wt. % of liquid(supernatant/water) is removed from the precipitate (or suspension) viaseparation processes known in the art, e.g., filtering, decanting,centrifuging, etc. In one embodiment, liquid in the precipitate isremoved via filtration with vacuum techniques or equipment known in theart, giving a wet filter cake. A wet filter cake is generally defined asfilter cake having approximately 10 to 50 wt. % liquid, thus beinggenerally free of water or other solvent such as methanol and the like.

In one embodiment, optional drying of the filter cake is performed underatmospheric conditions or under an inert atmosphere such as nitrogen,argon, or vacuum, and at a temperature sufficient to remove water butnot removal of organic compounds. In one embodiment, drying is performedat about 50 to 120° C. until a constant weight of the catalyst precursoris reached. In another embodiment, the drying is done at a temperaturebetween 50° C. to 200° C. for a period ranging from /2 hour to 6 hours.Drying can be done via thermal drying techniques known in the art, e.g.,flash drying, belt drying, oven drying, etc.

Post Precipitate Ligating: In the optional chelating step 26, thecatalyst precursor precipitate is treated with at least a ligating agentL. In one embodiment, chelating is carried out by passing organicligating agents/solvent vapor through the filter cake. In anotherembodiment, which is a more effective way of incorporating ligatingagents, the filter cake is washed in a solution containing the ligatingagent. The ligating agent used herein can be the same or different fromany ligating agent that may have been used/incorporated into the metalprecursors (reagents) in the precipitating step.

In one embodiment, a catalyst precursor incorporating a ligating agentapplied post precipitate forming shows a total pore volume of at least25% greater than a catalyst precursor that is chelated in the process offorming the precipitate, e.g., with the ligating agent(s) being added toone of the metal precursors or to the mixture of metal precursors, priorto or during the formation of the precipitate. In a second embodiment,the total pore volume increase is at least 40%. In a third embodiment,the total pore volume increase is at least 50%.

It is believed that in the post precipitate chelating step (after theformation of the precursor precipitate), the ligating agent provides theprecursor precipitate with additional high specific surface area for thesubsequent sulfiding step. It is also believed that in some embodiments,the ligating agent changes the surface charge of the precursor, whichsubsequently helps in keeping the particles separate (less clumpedtogether) in the drying step, for a catalyst with higher porosity.

Non-Agglomerative Drying: “Non-agglomerative drying” means a dryingprocess in which particle agglomeration is substantially prevented. Forexample, examination of the catalyst particle size in a wet centrifugecake indicates that the median particle size may be in the range of 1 to3 μm. However, after drying such a cake in the conventional manner, ovendrying or tray drying, the resulting median size of the particle is muchlarger as the particles remain stuck together/clump up of more than 40times the initial size. In some embodiments of tray drying, the filtercake dries out forming clumps or chunks (green body), requiringsubsequent milling to reduce the particle size of the precursor.

In non-agglomerative drying process, significant agglomeration isprevented with less clumping or with clumping of smaller sizes. In oneembodiment, the non-agglomerative drying produces particles having amedian size of less than 20 times the median size of the pre-dryingparticles. In another embodiment, the median size is less than 10 timesthe median size of the pre-drying particles. In a third embodiment, thenon-agglomerative drying produces particles having a median size of lessthan 5 times the median size of the particles pre-drying.

Examples of non-agglomerative drying methods include but are not limitedto flash drying, freeze drying, and fluidized bed drying, for themoisture content to be reduced to less than 15%. In one embodiment, themoisture content is reduced to less than 10%. In a third embodiment, toless than 5%. In a fourth embodiment, to less than 2%. In oneembodiment, after non-agglomerative drying, the dried catalyst precursorhas a median particle size of less than 40 μm.

In one embodiment, after a substantial amount of liquid is removed fromthe precipitate generating a wet filter cake, the wet filter cakeundergoes non-agglomerative drying 26 in a flash drying process. Inanother embodiment (as shown by dotted lines), the wet filter cake isfirst chelated before the non-agglomerative drying step. In oneembodiment, the filter cake is flash-dried at an air (or nitrogen)temperature of 70° C. to 250° C. in a period of less than 60 seconds. Inanother embodiment, the wet filter cake undergoes fluidized bed drying,wherein the particles surface area is exposed to the high volume airstream with the heat being transferred to the product surface byconvection in a short period of time, cutting down on particleagglomeration. Fluidized bed drying takes longer than flash drying, butstill allows the precursor particles to dry in a matter of minutesinstead of hours as in tray drying or oven drying and with substantiallyless clumping.

In comparative tests between tray dried samples (150° F. between 2 to 4hrs.) and flash dried samples, it is found that the flash driedprecursors have a total pore volume (via mercury prosimeter) of at least2 times the tray dried precursors. In another embodiment, the flashdried precursors have a total pore volume of at least 3 times the traydried precursors.

Forming Catalyst Precursor Mix For Shaping: In this step 30, the driedfilter cake is mixed together with water and other optional materialsincluding but not limited to shaping aids 32, peptizing agents, poreforming agents, and diluent materials 13. In one embodiment, reworkmaterial in the form of filter cake material, extrudable dough and/ordry particles/pieces of precursor materials from previous runs can beoptionally included the materials to form a new batch of catalystprecursor mix.

The precursor batch mixture is mixed for a sufficient period of time toobtain a mixture that is substantially uniform or homogeneous. Themixing time depends on the type and efficiency of the mixing technique,e.g., milling, kneading, slurry mixing, dry or wet mixing, orcombinations thereof and the mixing apparatus used, e.g., a pug mill, ablender, a double-arm kneading mixer, a rotor stator mixer, or a mixmuller. In one embodiment, the mixing time ranges from 0.1 to 10 hours.

In one embodiment, a shaping aid agent is added in a ratio of between100:1 and 10:1 (wt. % catalyst precursor to wt. % shaping aid). In oneembodiment, the shaping aid agent is selected an organic binder of thecellulose ether type and/or derivatives. Examples includemethylcellulose, hydroxybutylcellulose, hydrobutyl methylcellulose,hydroxyethylcellulose, hydroxymethylcellulose, hydroxypropylcellulose,hydroxypropyl methylcellulose, hydroxyethyl methylcellulose, sodiumcarboxy methylcellulose, and mixtures thereof. In another embodiment,the shaping aid is a polyakylene glycol such as polyethylene glycol(PEG). In yet another embodiment, shaping aids are selected fromsaturated or unsaturated fatty acid (such as politic acid, satiric acidor oleic acid) or a salt thereof, a polysaccharide derived acid or asalt thereof, graphite, starch, alkali stearate, ammonium stearate,stearic acid, mineral oils, and combinations thereof.

In one embodiment, a peptizing agent may be added to the mixture. Thepeptizing agent may be an alkali or an acid, e.g., ammonia, formic acid,citric acid, nitric acid, carboxylic acid, etc. In one embodimentwhether the catalyst precursor material is to be spray-dried, ammoniasolution from 10 to 28% strength can be added in amounts of from 50 to150 ml per 100 g of spray-dried material. In another embodiment, acidscan be employed in the form of aqueous solutions of from 2 to 4%strength, in amounts of from 10 to 20 ml per 100 g of spray-driedmaterial.

In another embodiment, a pore forming agent is also added to the mixturealong with the rework. Examples of pore forming agents include but arenot limited to mineral oils, steric acid, polyethylene glycol polymers,carbohydrate polymers, methacrylates, cellulose polymers, andcarboxylates which decompose upon being heated. Examples of commerciallyavailable cellulose based pore forming agents include but are notlimited to: Methocel™ (available from Dow Chemical Company), Avicel™(available from FMC Biopolymer), Morwet™ (from Witco) and Porocel™(available from Porocel).

In yet another embodiment, diluent materials can be added. The diluentmaterials added in this step can be the same as or different from anydiluent materials that may have been added to the step of forming theprecipitate from metal precursors above.

In one embodiment wherein the catalyst precursor is to be shaped viapelletizing, extrusion, or pressing, a sufficient amount of water isadded to the mixing batch to adjust the batch viscosity to a convenientlevel for plasticizing and shaping, i.e., a mixture of doughconsistency. In one embodiment, a sufficient amount of water is addedfor the mixture to have between 50 to 90% solids (LOI). In anotherembodiment, between 60 to 70% solids (LOI).

Shaping Process: In this step, the catalyst precursor mix is shaped intoformed particles, such as spheroids, pills, tablets, cylinders,irregular extrusions, merely loosely bound aggregates or clusters, etc.,using any of the methods known in the art including pelletizing,extrusion, tableting, molding, tumbling, pressing, spraying and spraydrying.

In one embodiment, a shaped catalyst precursor is formed via extrusion,using extrusion equipment known in the art, e.g., single screw extruder,ram extruder, twin-screw extruder, etc. In another embodiment, theshaping is done via spray drying at an outlet temperature ranging from100° C. to 320° C. In one embodiment, shaped catalyst precursor isextruded into extrudate having a diameter from about 1/16 to ⅙ of aninch. After extrusion the extrudate can be cut to suitable lengths,e.g., 1/16-inch to 5/16-inch, to produce cylindrical pellets.

Thermal Treatment: In one embodiment, the shaped catalyst precursor isair (or nitrogen) dried in a directly or indirectly heated oven, traydrier, or belt drier at about 50° C. to 325° C. for about 15 minutes to24 hours, and wherein the temperature is room temperature to dryingtemperature at a rate of 1-50° C. per minute. In one embodiment, thetemperature is ramped up at a slow rate of 1-2° C. per minute. In asecond embodiment, air drying is performed at a fast ramp up rate of atleast 25° C. per minute.

In one embodiment, after the thermal treatment, the shaped catalyst canbe optionally calcined at a temperature in the range of about 350° C. to750° C. in a suitable atmosphere, e.g., inerts such as nitrogen orargon, or steam. In yet another embodiment, the calcination is carriedout at a temperature between 350° C. to 600° C. In the calcinationprocess, the catalyst precursor gets converted into an oxide.

Sulfiding Step: The shaped catalyst precursor containing rework material61 can be sulfided to form an active catalyst, with the use of at leasta sulfiding agent 62 selected from the group of: elemental sulfur byitself, a sulfur-containing compound which under prevailing conditions,is decomposable into hydrogen sulphide; H₂S by itself or H₂S in anyinert or reducing environment, e.g., H₂. Examples of sulfiding agentsinclude ammonium sulfide, ammonium polysulfide ([(NH₄)₂S_(x)), ammoniumthiosulfate ((NH₄)₂S₂O₃), sodium thiosulfate Na₂S₂O₃), thiourea CSN₂H₄,carbon disulfide, dimethyl disulfide (DMDS), dimethyl sulfide (DMS),dibutyl polysulfide (DBPS), mercaptanes, tertiarybutyl polysulfide(PSTB), tertiarynonyl polysulfide (PSTN), and the like. In oneembodiment, hydrocarbon feedstock is used as a sulfur source forperforming the sulfidation of the catalyst precursor.

In the sulfiding step, shaped catalyst precursor is converted into anactive catalyst upon contact with the sulfiding agent at a temperatureranging from 70° C. to 500° C., from 10 minutes to 15 days, and under aH2-containing gas pressure. In one embodiment,

The total pressure during the sulfidation step can range betweenatmospheric to about 10 bar (1 MPa). If the sulfidation temperature isbelow the boiling point of the sulfiding agent, the process is generallycarried out at atmospheric pressure. Above the boiling temperature ofthe sulfiding agent/optional components (if any), the reaction isgenerally carried out at an increased pressure.

Use of the Catalyst: As catalyst precursors sometimes can be sulfidedin-situ, e.g., in the same hydrotreating reactors during hydrotreatment,catalyst performance can be characterized by the properties of thecatalyst precursors before sulfidation.

In one embodiment, the catalyst precursor is characterized as havingessentially a monomodal pore size distribution with a substantialportion of the pores being macropores. As used herein, essentiallymonomodal pore size distribution means that more than 90% of the poresbeing macropores, and less than 10% as mesopores. In one embodiment, thecatalyst precursor has a pore distribution such that more than 95% ofthe pore volume is presented as macropores. In another embodiment, morethan 97% of the pore volume is present as macropores. In yet anotherembodiment, more than 99% of the pores are macropores. Mesopores ifpresent have a pore volume ranging from 0.005 to 0.01 cc/g. In oneembodiment, the catalyst precursor is characterized as having a totalpore volume ranging from 0.08 to 2.0 cc/g. In another embodiment, thetotal pore volume ranges from 0.10 to 1. cc/g. In a third embodiment,the total pore volume is at least 0.12 cc/g. In a fourth embodiment fora catalyst precursor that is post precipitate ligated, the total porevolume is at least 0.15 cc/g.

As the catalyst precursor, and the sulfided bulk metallic catalystformed therefrom, have sufficient macropore sites and large pore volumeto overcome the diffusion limitations of heavy petroleum feeds, the bulkmetallic catalyst in one embodiment is particularly suitable forhydrotreating heavy petroleum feeds having an atmospheric residue (AR)boiling point in the range of 343° C. (650° F.)- to 454° C. (850° F.)and particularly above 371° C. (700° F.), under wide-ranging reactionconditions such as temperatures of from 200 to 450° C., hydrogenpressures of from 15 to 300 bar, liquid hourly space velocities of from0.05 to 10 h⁻¹ and hydrogen treat gas rates of from 35.6 to 2670 m³/m³(200 to 15000 SCF/B- or “Standard Cubic Feet per Barrel” of hydrocarboncompound feed to the reactor).

Heavy oil feeds having a boiling point greater than 343° C. (650° F.)are commonly characterized as having relatively high specific gravity,low hydrogen-to-carbon ratios, and high carbon residue. They containlarge amounts of asphaltenes, sulfur, nitrogen and metals, whichincrease hydrotreating difficulty with their large molecular diameter.In one embodiment with the monomodal distribution of primarilymasopores, the bulk catalyst is particularly suited for hydrotreatingheavy petroleum feeds having an average molecular diameter ranging from0.9 nm to 1.7 nm (9 to 17 angstrom), providing an HDN conversion levelof >99.99% (700° F.+ conversion), lowering the sulfur level in fractionabove 700° F. boiling point to less than 20 ppm in one embodiment, andless than 10 ppm in a second embodiment. In one embodiment, the bulkcatalyst is particularly suited for hydrotreating a heavy petroleum feedhaving an average molecular diameter ranging from 0.9 nm to 1.7 nm. Inyet another embodiment, the bulk catalyst is particularly suitable fortreating a heavy oil feed having an average molecular weight Mn rangingfrom 300 to 400 g/mole.

Besides having a unique pore size distribution of essentially beingmodomodal with macropores, the precursor for forming the catalyst alsoexhibits other desirable properties, including a compact bulk density(CBD) of at most 1.6 g/cc; a crush strength of at least about 4 lbs; andan attrition loss of less than 7 wt. %. In one embodiment, the attritionloss is less than 5 wt. %. In a second embodiment, the CBD is at most1.4 g/cc. In a third embodiment, the CBD is at most 1.2 g/cc. In afourth embodiment, the CBD is in the range of 1.2 g/cc to 1.4 g/cc.

In one embodiment, the catalyst precursor has a particle density ofequal or less 2.5 g/cc. In another embodiment, the particle density isequal or less than 2.2 g/cc.

In one embodiment, the catalyst precursor is characterized has having asurface area measured by the BET method, using nitrogen as adsorbate,ranging from 40 to 400 m²/g. In a second embodiment, a surface arearanging from 60 to 300 m²/g. In a third embodiment, a surface arearanging from 100 to 250 m²/g. In one embodiment, the catalyst precursorhas a combined high surface area and high volume pore with a surfacearea of at least 150 m²/g.

EXAMPLES

The following illustrative examples are intended to be non-limiting.

Example 1 Ni—Mo—W-Maleate Catalyst Precursor

A catalyst precursor of the formula (NH₄) {[Ni_(2.6)(OH)_(2.08)(C₄H₂O₄²⁻)_(0.06)] (Mo_(0.35)W_(0.65)O₄)₂} was prepared as follows: 52.96 g ofammonium heptamolybdate (NH₄)₆Mo₇O₂₄.4H₂O was dissolved in 2.4 L ofdeionized water at room temperature. The pH of the resulting solutionwas within the range of 2-3. 52.96 g of ammonium heptamolybdate(NH₄)₆Mo₇O₂₄.4H₂O was dissolved in the above solution. The pH of theresulting solution was within the range of 5-6. 73.98 g of ammoniummetatungstate powder was then added to the above solution and stirred atroom temperature until completely dissolved. 90 ml of concentrated(NH₄)OH was added to the solution with constant stirring. The resultingmolybdate /tungstate solution was stirred for 10 minutes and the pHmonitored. The solution had a pH in the range of 9-10. A second solutionwas prepared containing 174.65 g of Ni(NO₃)₂.6H₂O dissolved in 150 ml ofdeionized water and heated to 90° C. The hot nickel solution was thenslowly added over 1 hr to the molybdate/tungstate solution. Theresulting mixture was heated to 91° C. and stirring continued for 30minutes. The pH of the solution was in the range of 5-6. A blue-greenprecipitate formed and the precipitate was collected by filtration. Theprecipitate was dispersed into a solution of 10.54 g of maleic aciddissolved in 1.8 L of DI water and heated to 70° C. The resulting slurrywas stirred for 30 min. at 70° C. and filtered.

Example 2 Ni—Mo—W Catalyst Precursor

A catalyst precursor of the formula (NH₄){[Ni_(2.6)(OH)_(2.08)](Mo_(0.35)W_(0.65)O₄)₂} was prepared as follows:52.96 g of ammonium heptamolybdate (NH₄)₆Mo₇O₂₄.4H₂O was dissolved in2.4 L of deionized water at room temperature. The pH of the resultingsolution was within the range of 5-6. 73.98 g of ammonium metatungstatepowder was then added to the above solution and stirred at roomtemperature until completely dissolved. 90 ml of concentrated (NH₄)OHwas added to the solution with constant stirring. The resultingmolybdate/tungstate solution was stirred for 10 minutes and the pHmonitored. The solution had a pH in the range of 9-10. A second solutionwas prepared containing 174.65 g of Ni(NO₃)₂.6H₂O dissolved in 150 ml ofdeionized water and heated to 90° C. The hot nickel solution was thenslowly added over 1 hr to the molybdate/tungstate solution. Theresulting mixture was heated to 91° C. and stirring continued for 30minutes. The pH of the solution was in the range of 5-6. A blue-greenprecipitate formed and the precipitate was collected by filtration,giving a filtercake.

Example 3 Ni—Mo—W Maleate Catalyst Precursor—Post Precipitate Chelating

The precipitate of Example 2 was dispersed into a solution of 10.54 g ofmaleic acid dissolved in 1.8 L of DI water and heated to 70° C. Theresulting slurry was stirred for 30 min. at 70° C. then filtered.

Example 4 Agglomerative vs. Non-Agglomertive Drying of Filter Cake

The catalyst precursor of Examples 1-3 in the form of filter cake(having about 50% moisture, particle size averaging 1.66 μm D50 andmaximum of 7.5 μm) was flash dried in a 2″ ThermaJet dryer with a 600°F. inlet temperature and 220-325° F. outlet temperature, less than 1residence time of less than 1 minute, giving apowder having about 8 to10% moisture. The Ni—Mo—W precursor of Example 2 was also tray-dried atabout 150° F. for 2 to 4 hours. Table 1 contains results comparingtray-drying vs. flash-drying for the Ni—Mo—W precursor of Example 2:

TABLE 1 N₂ Hg (total) Microporosity* Macroporosity Ni—Mo—W Surface porevolume pore volume Pore volume pore volume Sample area m²/g cc/g cc/gcc/g cc/g flash-dried 152 0.106 0.314 0.003 0.266 tray-dried 70 0.0750.108 0.005 0.027 *nil - amount measured within instrumental error

Example 5 Forming Shaped Catalyst Precursors

In this example, 40 g of dried catalyst precursor prepared as perexamples 1-3 was mixed with 0.8 g of methocel, (a commercially availablemethylcellulose and hydroxypropyl methylcellulose polymer from DowChemical Company), and approximately 7 g of DI water was added. Another7 g of water was slowly added until the mixture was of an extrudableconsistency. The mixture was extruded using any of a double barrel Wolfextruder with a 27½″ screw and full-length of 33½″ and with 1/16″ die.The extrudate was cut into pellets with length of about ⅛″ to ½″.

After extrusion, the catalyst precursor pellets (Ni—Mo—W andNi—Mo—W-maleate) were dried under N₂ at 120° C., and measured for porevolume and surface area. The results are presented in Table 2 asfollows:

TABLE 2 Surface N₂ Hg macro Hg meso area BET meso pore pore volume porevolume Samples m²/g volume cc/g cc/g cc/g Ni—Mo—W 60 0.03 0.12 0.03maleate Ni—Mo—W 80 0.01 0.10 0.01 Ni—Mo—W 96 0.03 0.18 0.03 maleatepost-precipitate ligating

Example 6 Sulfidation with DMDS Gas Phase

The samples of shaped catalyst precursors from Example 5 were placed ina tubular reactor. The temperature was raised to 450° F. at a rate of100° F./hr under N_(2(g)) at 8 ft³/hr. The reaction was continued for 1hour after which time the N₂ was switched off and replaced with H₂ at 8ft³/hr and 100 psig for 1 hour. The H₂ pressure was then increased to300 psig and maintained for less than 1 hr. after which time dimethyldisulfide (DMDS) was added at a rate of 4 cc/hour and then reactionallowed to proceed for 4 hr. The catalyst precursor was then heated to600° F. and the rate of DMDS addition increased to 8 cc/hr. Thetemperature was maintained at 600° F. for 2 hours after which timesulfidation was complete.

Example 7 Hydroprocessing Process

The samples from Example 6 were tested under severe hydroprocessingconditions and activities with respect to hydrocracking, HDS, and HDNactivity were evaluated, along with the volumetric shrinkage rate. Theheavy oil feedstock was a heavy oil feed with a boiling point above 700°F., a sulfur content of 31135 ppm, a nitrogen content of 31230 ppm, andother properties as presented in Table 3. The reactor conditions includea pressure of 2300 psi, an H₂ gas rate of 5000 SCFB, and an LHSV of0.75.

TABLE 3 Heavy Oil feed Properties API Gravity 20.0 N, ppm 1100 S, wt %2.72 Carbon, wt % 85.6 22 compounds Aromatics, vol % 35.0 Naphthenes,vol % 27.8 Paraffins, vol % 13.5 Sulfur compounds, vol % 23.7 Simdist,wt % 0.5/5 640/689  10/30 717/800  50/ 866  70/90  930/1013  95/99 163/1168

Results obtained from the run included a 700° F.+conversion of at last40%, sulfur reduction to less than 10 ppm in the stripper bottoms, N₂level to less than 25 ppm in the stripper bottoms.

For the purposes of this specification and appended claims, unlessotherwise indicated, all numbers expressing quantities, percentages orproportions, and other numerical values used in the specification andclaims, are to be understood as being modified in all instances by theterm “about.” Accordingly, unless indicated to the contrary, thenumerical parameters set forth in the following specification andattached claims are approximations that can vary depending upon thedesired properties sought to be obtained by the present invention. It isnoted that, as used in this specification and the appended claims, thesingular forms “a,” “an,” and “the,” include plural references unlessexpressly and unequivocally limited to one referent. As used herein, theterm “include” and its grammatical variants are intended to benon-limiting, such that recitation of items in a list is not to theexclusion of other like items that can be substituted or added to thelisted items.

This written description uses examples to disclose the invention,including the best mode, and also to enable any person skilled in theart to make and use the invention. The patentable scope is defined bythe claims, and can include other examples that occur to those skilledin the art. Such other examples are intended to be within the scope ofthe claims if they have structural elements that do not differ from theliteral language of the claims, or if they include equivalent structuralelements with insubstantial differences from the literal languages ofthe claims. All citations referred herein are expressly incorporatedherein by reference.

1. A catalyst precursor, upon sulfidation, forms a bulk multi-metalliccatalyst for hydrotreating a hydrocarbon feed under hydroprocessingconditions, the catalyst precursor comprising at least a Group VIB metalcompound; at least a promoter metal compound selected from Group VIII,Group IIB, Group IIA, Group IVA and combinations thereof, optionally atleast a ligating agent; optionally at least a diluent; wherein thecatalyst precursor has an essentially monomodal pore size distributionwith at least 90% of the pores being macropores and a total pore volumeof at least 0.08 g/cc.
 2. The catalyst precursor of claim 1, wherein thecatalyst precursor has a total pore volume of at least 0.10 g/cc.
 3. Thecatalyst precursor of claim 1, wherein the catalyst precursor has atotal pore volume of at least 0.12 g/cc.
 4. The catalyst precursor ofclaim 1, wherein the catalyst precursor has an essentially monomodalpore size distribution with at least 95% of the pores being macropores.5. The catalyst precursor of claim 1, wherein at least 97% of the poresare present as macropores.
 6. The catalyst precursor of claim 1, whereinthe catalyst precursor has a compact bulk density of at most 1.6 g/cc.7. The catalyst precursor of claim 6, wherein the catalyst precursor hasa compact bulk density of at most 1.4 g/cc.
 8. The catalyst precursor ofclaim 6, wherein the catalyst precursor has a compact bulk density inthe range of 1.2 to 1.6 g/cc.
 9. The catalyst precursor of claim 1,wherein the catalyst precursor has a BET surface area in the range of 40to 400 m²/g.
 10. The catalyst precursor of claim 9, wherein the catalystprecursor has a BET surface area in the range of 100 to 250 m²/g. 11.The catalyst precursor of claim 1, wherein upon sulfidation, forms abulk-multi-metallic catalyst for hydrotreating hydrocarbon feed has anatmospheric residue boiling point of at least 343° C. (650° F.) with anHDN conversion rate of at least 99%.
 12. The catalyst precursor of claim11, for forming a bulk multi-metallic catalyst for hydrotreating ahydrocarbon feed has an atmospheric residue boiling point of at least371° C. (700° F.) with an HDN conversion rate of at least 99%.
 13. Thecatalyst precursor of claim 11, wherein the hydrocarbon feed has anaverage molecular diameter ranging from 0.9 nm to 1.7 nm.
 14. Thecatalyst precursor of claim 11, wherein the hydrocarbon feed has anaverage molecular weight Mn ranging from 300 to
 400. 15. The catalystprecursor of claim 1, wherein the catalyst precursor is of the formulaA_(v)[(M^(P))(OH)_(x)(L)^(n) _(y)]_(z)(M^(VIB)O₄), wherein A is at leastone of an alkali metal cation, an ammonium, an organic ammonium and aphosphonium cation; M^(P) is the at least a promoter metal compound, andM^(P) is selected elected from Group VIII, Group IIB, Group IIA, GroupIVA and combinations thereof; L is at the least a ligating agent,M^(VIB) is the at least a Group VIB metal, having an oxidation state of+6; M^(P):M^(VIB) has an atomic ratio of 100:1 to 1:100;v−2+P*z−x*z+n*y*z=0; and 0≦y≦−P/n; 0≦x≦P; 0≦v≦2; 0<z.
 16. The catalystprecursor of claim 15, wherein M^(P) is at least a Group VIII metal,M^(VIB) is selected from molybdenum, tungsten, and combinations thereof,and L is at least one of carboxylates, enolates, and combinationsthereof.
 17. The catalyst precursor of claim 16, wherein M^(VIB) is amixture of at least two Group VIB metals, e.g., molybdenum and tungsten.18. The catalyst precursor of claim 15, wherein L is selected fromcarboxylates, carboxylic acids, aldehydes, ketones, aldehydes,hemiacetals, formic acid, acetic acid, propionic acid, maleic acid,malic acid, cluconic acid, fumaric acid, succinic acid, tartaric acid,citric acid, oxalic acid, glyoxylic acid, aspartic acid, alkane sulfonicacids, aryl sulfonic acids, maleate, formate, acetate, propionate,butyrate, pentanoate, hexanoate, dicarboxylate, and combinationsthereof.
 19. The catalyst precursor of claim 15, wherein L is maleate20. The catalyst precursor of claim 11, wherein the catalyst precursoris of the formula (X)_(b)(Mo)_(c)(W)_(d)O_(z); wherein X is Ni or Co,the molar ratio of b:(c+d) is 0.5/1 to 3/1, the molar ratio of c: dis >0.01/1, and z=[2b+6 (c+d)]/2.
 21. The catalyst precursor of claim20, wherein X is Ni.